Methodology
How the pumpkin spice launch dates were built
62 chain-years, 54 of them dated to the day and used in the statistics, dataset 2026-09-09. The study is on this page; everything below is the rulebook it was built under.
What counts as a launch.
The date a chain's fall lineup including pumpkin went on sale nationwide in the United States, as given by the chain's own announcement or contemporaneous reporting. Regional tests, one-day stunts and grocery products are not launches. Krispy Kreme's 2017 return was a single pumpkin doughnut for one day; that row is recorded, flagged as a stunt, drawn as a hollow point, and excluded from every fit. Its separate one-day doughnut events in other years (for example October 26, 2016) are noted but are not the season launch. Starbucks' October 10, 2003 date was a 100-store test market; it is kept, drawn as a marked point, and excluded from every regression.
Two sources per date, and what each status means.
A row is confirmed when two independent sources agree (a chain announcement plus a news report, or one of those plus a Wayback Machine homepage bracket consistent with the date). A row with one source and no bracket is reported. A year with nothing verifiable is a gap and stays in the table as a gap. No date was estimated, interpolated or inferred from a pattern. Every dated row carries a verbatim, date-bearing quote next to its URL in the downloadable CSV.
Archived originals beat edited pages.
Dunkin's live newsroom page for its 2022 fall menu was edited after publication to imply an August 10 launch. The Wayback Machine capture of August 11, 2022 preserves the original wording, 'Officially launching on August 17', which is the date used here. Any dataset showing August 10 for that year copied the edited page.
Precision, and what enters the maths.
Only day-precision rows enter the statistics. Starbucks 2004 and 2006 are known to the month, 7-Eleven 2021 to the week, and Dunkin' 2015 only as a published two-week range (August 17 to 31); all four appear in the table and are excluded from every calculation.
The equinox metric.
Each launch is expressed as days before that year's September equinox. The equinox instant is computed with the mean-equinox polynomial in Meeus, Astronomical Algorithms chapter 27, which is accurate to well under an hour, then converted to US Eastern daylight time and truncated to a date. Using the equinox rather than a fixed calendar date removes leap-day artefacts and answers the question people actually ask, which is how far before autumn the season starts.
Trend statistics.
Ordinary least squares of days-before-equinox on year, per chain, with a 95% confidence interval from the t distribution. Each chain is fitted on its full-lineup rows and separately on 2020 onward. A composite is fitted on the Starbucks and Dunkin' rows together, the two long series, on all years, on years to 2019, and on 2020 onward. The July 4 extrapolation uses the pre-2020 composite slope and Krispy Kreme's own slope, and is presented as a what-if: the 2020s fits are flat and it is not a forecast.
What was dropped, and why.
The brief's Google Trends layer (the first week each year that search interest crosses a threshold, as an independent creep signal) was dropped on 2026-09-09. Google's official Trends API is still an application-gated alpha and the unofficial routes are unreliable, so the layer could not be built reproducibly. The creep statistics stand on launch dates alone. Costa (UK) was considered and skipped: it has no pumpkin range, and relabelling its autumn menu would have changed the question.
The 2026 rows.
All four 2026 dates are confirmed by two sources: Starbucks August 25 (Starbucks Stories, August 3; Fox 4, August 5), Krispy Kreme August 11 (krispykreme.com, '8/11/26 through 11/2/26'; The Takeout, August 11), Dunkin' August 19 (Sacramento Bee, August 17, citing Dunkin's Instagram; USA TODAY, August 19), 7-Eleven August 27 (PR Newswire, a corrected release dated August 27; NACS, August 28). One caveat is recorded: Dunkin's own release is dated August 19 and headlines the pumpkin menu but only dates the Alix Earle meal as available that day. Krispy Kreme also ran a one-week return of its Pumpkin Spice Original Glazed from August 27 to 30; that is not the season launch.
Reproducing it.
The study directory holds the raw cached sources, a manifest of every fetch with URL, timestamp and HTTP status, the candidate table, the Wayback corroboration pass (resumable and rate-limited), the build script that assigns statuses, the analysis script that computes every number on this page, and the chart and site-data generators. Anyone can go from raw to final with one command per step.